Published 29 April 2014
Climate change will increase the spread of infectious disease across the globe. As we experience significant global changes in temperature and weather patterns, we can expect that both the range of infectious diseases and the timing, intensity and location of disease outbreaks will become more severe. This, in turn, is likely to contribute to the increase in antibiotic-resistant bacteria. The emergence of “superbugs” continues to rise and medical industries, scientists and the World Health Organisation (WHO) are in a race to provide newer, more effective antibiotics to tackle this threat to our healthcare system. As a veterinary scientist, I’m interested in exploring both the role of animal agriculture in the rise of these superbugs and the implications for future efficacy of antibiotics – both made all the more urgent by the impacts of a changing climate
More than half the world’s antibiotics are attributed to agricultural use. Antibiotics are routinely used in farm animals to treat, as well as prevent, diseases exacerbated by unsanitary living conditions and are added to animal feed in small amounts to accelerate their growth rates, and to supply a world demanding to be fed at a faster, cheaper and super-sized pace. For decades, it has been known that the overuse and misuse of antibiotics – in the medical and agricultural industries – promotes the emergence of antibiotic-resistant pathogens. Using sub-therapeutic doses, or ineffectively targeting the intended bacteria, leads to survival of the fittest; resistant bacteria remain and reproduce exponentially. Evolution of resistance can originate from mutations conveniently equipping bacteria with immunity to certain antibiotics, or through their ability to exchange drug-resistant genes between one another. Transference of these superbugs to our population via ingestion of meat and other animal products, direct contact with reservoir animals, or secondary contact with individuals exposed to resistant bacteria is a very real danger. Our rapidly growing population and predilection for food imports and international travel compounds the risk of drug-resistant bacteria spreading.
This is cause for concern. Without substantial surveillance programs that are able to monitor antibiotic resistance in animals we are at risk of creating bacteria that we simply cannot control. As Dr Margaret Chan, Director of WHO, notes, this would spell an end to modern medicine as we know it. Things as common as a strep throat or a scratch to the knee could once again kill. Due to the inherent risks of selecting for resistant bacteria with prolonged low doses, there have been a myriad of proposed bans on non-therapeutic use in food-producing animals, and suggested outright bans on certain antibiotics critical in human medicine, by global networks of science academies.
Does the agricultural industry and community appreciate the true gravity of this situation? Already, and unbeknownst to most of the public, there are approximately 25,000 deaths in Europe, and 23, 000 deaths in the U.S. annually due to resistant infections. Not to mention, the estimated annual $250 million cost to the Australian health-care budget and additional $400 million burden to the community. And mortalities have included young and fit city-dwelling individuals, as featured on the Infectious Disease Society’s website, which documents victims of antibiotic-resistant infections. Ricky Lannetti was a healthy 21 year old football player in Pennsylvania who died after contracting an MRSA. Closer to home, Ian Thorpe was the most recent publicised victim of a drug-resistant infection, after a shoulder operation, which has jeopardised any future swimming career.
While there are significant efforts directed towards the development of novel antibiotics to keep up with fast-evolving bacteria, more must be done. WHO’s latest publication on solutions to the antimicrobial resistance threat, include recommendations to implement antibiotic-resistance surveillance programs and reduce agricultural use, as well as banning their use as growth-promotants in animal feed. Included in her 2013 report on infectious disease and antibiotic resistance, Professor Dame Sally Davies (UK Chief Medical Officer) emphasised the need to add antibiotic resistance to the UK government’s list of threats to national security.
These sentiments of urgency are not isolated. Indeed, Nature’s recent publications criticise antibiotic overuse in animal agriculture, warning that if “farmers do not rein in the use of antibiotics for livestock, people will be severely affected.” Unlike Denmark, Norway, Sweden, and Canada – Australia, and the rest of the world, has no antimicrobial resistance surveillance program. Although the National Residues Survey (NRS) in Australia monitors the presence of antibiotic residues to ensure compliance with accepted levels, there is no such resistance monitoring in place.
Does this mean the development of resistance is futile? The response of governments worldwide will determine this. Their ability to collaborate with veterinary, medical, and agricultural industries to implement policies and regulations will be essential in safeguarding the remaining antibiotics and achieving WHO’s global health goals. Government support for the most crucial sectors of their workforce – the Department of Environment and Department of Agriculture – is essential. Time is of the essence as our climate continues to change.
Sy Woon is a final year veterinary student from the University of Sydney, currently working as Sentient, The Veterinary Institute for Animal Ethics’ Social Media Coordinator as well as Project Officer for The Medical Advances Without Animals (MAWA) Trust.